In this article we are going to review how to remove a dent from a automotive part.  We’ve determined that the panel is mild steel and repairing the damage would be a better choice than to replace the panel.  Now we need to develop a repair plan and decide which repair method to use on the damage.
First In Last Out
The first thing that you want to determine is the direction of damage.  This is important so you can reverse the damage during repairs.  In collision repair we have a general rule “the first in last out rule.”  This means that the direct damage or point on impact is the area first hit in an accident, which makes it the first in.  Therefore, this should be that last area to repair.  Direct damage is the most obvious damage as it is easy to visually see.  If you try to pull the direct damage first, you will stretch the metal, pull highs in the metal, and still have lows.  You are basically going to chase your damage around while work hardening the metal until the metal become to work hardened, brittle and cracks.

Direct and Indirect Damage
Indirect damage is the damage that is caused by the direct damage.  For example, as the point of impact is pushed in, it causes the surrounding metal to slightly move as well.  If pushed far enough, the indirect damage can cause misaligned body gaps, cracked seam sealer, and/or popped spot welds.  The indirect damage is less noticeable as it may not be visually noticeably without close observation.  The indirect damage is the damage the happened last during the accident, therefore, this damage should be repair first.  Always remember the “first in last out “rule when developing a repair plan.  This will save you hours of time and frustration when it is all done.

Choosing a Repair Method
Once the damage is analyzed and you have determined the direction of damage, and the direct and indirect damage.  Now it is time to decide which repair method is the best choice for the repair.  If you can get to both sides of the panel a hammer and dolly method may be the easiest repair method.  If you can not gain access to both sides of the panel a stud-nail gun may be a better choice.  Other considerations, such as corrosion protection and noise preventions  should be considered as well.  This will be covered at a later time.

Don’t Force The Metal, But Rather Roll The Metal Back To Its Shape
Regardless of the repair method, the same principle apply.  Start with the indirect damage and pull out on the lows and push in on the highs.  You should roll the metal back into shape, rather than try to force it back into shape.  Forcing the metal back into its shape may result in highs and stretched metal.  condition.  Pulling on the lows while rolling the highs out of the metal is the key to metal straightening, regardless of repair method used.